In order to import a .sqlite file to CartoDruid, we must press the + button from the table of contents and then select Add → Vector Layer → Load Sqlite file.
We select the file to load and define the characteristics of the new layer.
We have a post on our website that details the import of Sqlite files to CartoDruid:
https://www.cartodruid.es/mporting-shapefile-.sqlite-files-to-cartodruid